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Re: [Spca50x-devs] GSPCA driver and serial ports




The board is a VIA CN700 chipset with an embedded 1.5Ghz VIA CN700 NANO BGA processor. The serial ports are integrated into the motherboard, set to 3F8, IRQ 4 and 2F8, IRQ 3. In the bios they can be found under Onboard Super IO.

Thanks,
Scott Moore

On 4/2/07, Joel Crisp <jcrisp@xxxxxxxxxxx> wrote:
Hi

I'm the original author of the SPCA50x module. It was never a serial
port driver, it has been a USB driver all along. Where did your
colleague find that information?

Can you give me the details of your embedded board? There may be an
IRQ conflict, but if so it is likely to be between the USB controller
and the GPIO controller which will be managing the serial ports. In
this case, I would suggest disabling the on-board GPIO if it is a
desktop class machine or looking to see if you can re-configure the
IRQ mappings if it is embedded. Have you considered using a
USB->Serial bridge?

The SPCA50x driver doesn't hit the USB controller directly, instead it
sends messages to the kernel top side of the kernel driver which is
then responsible for calling the appropriate hardware driver to manage
the USB controller. This means that there is a high degree of
isolation of the SPCA50x driver from the USB hardware. It is similar
to using a socket vs. hitting the network card registers.

I think on balance it is more likely to be a CPU usage issue - low
power embedded boards can struggle with the video stream. If you are
doing Robotic control, you may want to snap individual frames rather
than a continuous stream.

Joel

On 4/2/07, Scott Moore <scott.moore.utd@xxxxxxxxx> wrote:
> I am a university student working on a robotics project using the gspca
> driver to run a Creative Webcam Live!
> After getting the camera working, we returned to our (previously working)
> servo controller code, which uses the serial ports on our board. We can no
> longer send information from the serial port, though everything appears
> correct in stty, /dev, and /proc/interrupts. My colleague says he found a
> post on a French website related to the camera driver where someone else had
> a similar problem. He said that one of the developers had posted that the
> driver had initially been written as a serial driver or some such, and
> therefore interfered with the serial port IRQs, or disabled them. I do not
> know if this is the case, as I can't get the ports to work with the module
> unloaded either. If anyone knows about the effect gspca might have on serial
> functionality, please let me know.
>
> Many thanks,
> Scott Moore
> University of Texas at Dallas
>
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